Known filter cigarette assembling machines comprise a filter attachment unit for attaching a filter and tobacco rod to form a filter cigarette. In a known filter attachment unit, a “double length” filter rod (also called a “2-up” rod) is aligned with two tobacco rods at either end, and the three rods are wrapped with a wrapper known as a “tipping paper” so as to join them together. The centrally positioned 2-up filter rod is then cut into two so as to form two filter cigarettes. This process is well known per se to those skilled in the art.
Known filter rods and tobacco rods are conveyed in a filter attachment unit by a plurality of cylindrical drums, with rod articles passing from drum to drum as they are conveyed through the unit. Known drums have a plurality of grooves for holding rod articles during transport, the grooves being spaced around the curved periphery of a drum, with each groove extending in the direction of the drum axis.
Certain drums are configured so that particular operations are carried out as the rod articles are conveyed by the drum. For example known filter attachment machines include a swash plate drum for longitudinally compressing two tobacco rods and a 2-up filter rod before tipping paper is applied, and a rolling drum which co-operates with a roll hand to wrap a tipping paper segment around the three rods. Other known drums include cutting drums which cooperate with a cutting knife to cut rod articles, separating drums for separating rod articles, inspection drums to inspect for the presence of filters or to carry out a leakage test, laser drums to burn small perforations in filter rods, and turning drums to change the orientation of cigarettes. Other known drums include transfer drums (also referred to as “intermediate drums”), takeover drums and feed drums. Known filter attachment machines also include a tipper unit for supplying individual cut segments of tipping paper (known as tipping “patches”) and a glue unit for applying glue to the tipping paper.
Known filter attachment units also include a machine controller which controls the drums of the unit. Such controllers can control the acceleration, deceleration and speed of drums and the registration of the rotational position of drums relative to one another, and can also carry out self-diagnosis on the drums.